The present invention relates to an apparatus for aligning medical instruments such as a cutting blade during a surgical procedure. More particularly, the present invention relates to an apparatus for aligning a resection guide for use in arthroplastic surgery of a patient's knee.
Arthroplasty is a known surgical procedure for replacing the knee joint which has been damaged due to disease or trauma. Total knee arthroplasty involves the replacement of portions of the patella, femur and tibia with artificial knee prostheses. In these prostheses, the articular surfaces of the bones are “resurfaced” with articular bearing components. One important aspect of these procedures is the correct resection of the bones. These resections must provide planes which are correctly angled in order to properly accept the prosthetic components.
Recently, various computerized navigation systems have been introduced to aid the practitioner during different surgical procedures. These systems include multiple video cameras which are deployed above the surgical site and a plurality of dynamic reference frame (DRF) devices, also known as trackers, which are attached to body parts and surgical instruments. The trackers can be LED devices or reflective spheres which are visible to the cameras. These trackers are attached to body parts and the surgical instruments and preferably include light emitting devices, such as light emitting diodes which are visible to the video cameras. The trackers communicate position information to a camera system located in the operating room. The camera system is connected to a computer which tracks the location of the tracker and the patient and displays the relationship on a CRT. Using software designed for a particular surgical procedure, a computer receiving input from the cameras guides the placement of surgical instruments such as cutting blocks for bone resection.
When using resurfacing type knee prostheses, the articular surface of the distal femur and proximal surface of the tibia are resurfaced with artificial knee components. Various apparatus are available to the surgeon for assisting in guiding a medical instrument such as a cutting blade for marking the femoral and tibial cuts which establish the desired resected surfaces. United States Patent Application Publication discloses one such apparatus for aligning the instruments during surgery. However, the disclosed apparatus is mechanically complex, and cumbersome and not intuitive to use. U.S. Pat. No. 5,681,316 is another example of a resection guide that is complex, cumbersome and not intuitive to use. Thus there is a need for a simple, easy to use and intuitive adjustable resection guide for aligning medical instruments during surgery.